Crimp height monitor

Abstract

An apparatus and a process are provided for assessing the quality of crimped electrical terminations of a terminal to a wire. The apparatus includes a strain gauge incorporated into a crimp press for measuring the strain generated in the press during each crimping cycle. The strain gauge is operatively connected to a controller which generates appropriate signals in response to strain measurements that are not within an acceptable range. The crimp press may further be operative to selectively adjust the crimp height or the length of the crimp stroke. The adjustment may be operatively connected to the controller, such that the crimp press is self-adjustiong and accommodates the gradual wearing of the crimp tools.

I claim: 
     
       1. A crimp press for crimping an electrically conductive terminal to a wire, said press comprising a frame, an anvil mounted to the frame and having means for receiving at least one said terminal and at least one said wire thereon, a punch movable relative to the frame and the anvil for crimping selected portions of the terminal into engagement with the wire, wherein the improvement comprises: force measurement means mounted to said crimp press for measuring the maximum force generated in the crimp press during each cycle of the punch; and   control means operatively connected to the force measurement means for comparing the measured force to an acceptable range of forces and for generating a signal in response to said measured force being outside the acceptable range;   wherein the control means further comprises averaging means for calculating the average maximum force over a selected number of crimp cycles, said control means further being operative to compare the average maximum force to a minimum acceptable average maximum force and for generating a signal in response to an average measured maximum force being less than the minimum acceptable average maximum force.   
     
     
       2. A crimp press for crimping an electrically conductive terminal to a wire, said press comprising a frame, an anvil mounted to the frame and having means for receiving at least one said terminal and at least one said wire thereon; crimp height adjustment means for providing a selectively adjustable crimp height, a punch movable relative to said frame and said anvil for crimping selected portions of the terminal into engagement with the wire, wherein the improvement comprises: force measurement means mounted to said crimp press for measuring the maximum force generated in the crimp press as a result of said punch crimping said terminal during each cycle of the punch, said force measurement means comprising piezoelectric means for converting dimensional changes in the crimp press to electrical signals; and   control means for storing an acceptable ranges of forces corresponding to crimp heights and operatively connected to the force measurement means for comparing the measured maximum force to an acceptable range of forces for a selected crimp height and for generating a signal in response to said measured maximum force being outside the acceptable range for the selected crimp height.   
     
     
       3. A crimp press as in claim 2 wherein the adjustment means comprises a motor means for effecting the adjustment, the motor means being operatively connected to the control means. 
     
     
       4. A crimp press as in claim 2 wherein the adjustment means comprises means for adjusting the position of the punch relative to the anvil. 
     
     
       5. A crimp press as in claim 4 comprising an insulation punch for crimping a first portion of the terminal to insulation on the wire and a conductor punch for crimping a second portion of the terminal to a conductor in the wire, said crimp height adjustment means being operative to independently adjust the position of the insulation punch and the conductor punch in response to signals from the control means. 
     
     
       6. A crimp press as in claim 2 further comprising visible display means operatively connected to the control means for producing a visible display of forces sensed by the force sensing means. 
     
     
       7. A crimp press as in claim 2 wherein the force measurement means is mounted to the frame of the crimp press. 
     
     
       8. A crimp press as in claim 2 further comprising visible display means operatively connected to the control means for producing a visible display of forces sensed by the force sensing means. 
     
     
       9. A method for measuring the quality of a crimp termination of an electrically conductive terminal to a wire, said method comprising the steps of presenting at least one terminal to a crimp press, presenting a wire into proximity with the terminal and operating the crimp press for crimping selected portions of the terminal into engagement with the wire, wherein the improvement comprises: measuring the maximum forces generated by the crimp press during each of a selected plurality of sequential operations of said crimp press;   storing the value of the measured force for each of the selected plurality of sequential operations of the crimp press;   averaging the maximum forces measured in said selected plurality to determine a measured average maximum force;   comparing said average to an acceptable range of averages; and   generating an adjustment signal in response to a measured average maximum crimp force being outside the acceptable range of average crimp forces.   
     
     
       10. A method as in claim 6 further comprising the step of automatically adjusting the movement of the punch in response to an average measured force outside the acceptable range of averages. 
     
     
       11. A method as in claim 10 further comprising the step of counting the number of adjustments automatically made to the movement of the punch and generating a change tool signal after making a selected number of adjustments.